On 2/12/26 5:28 PM, Shameer Kolothum Thodi wrote:
>
>> -----Original Message-----
>> From: Nicolin Chen <[email protected]>
>> Sent: 12 February 2026 06:52
>> To: Eric Auger <[email protected]>
>> Cc: Shameer Kolothum Thodi <[email protected]>; qemu-
>> [email protected]; [email protected]; [email protected];
>> Nathan Chen <[email protected]>; Matt Ochs <[email protected]>;
>> Jiandi An <[email protected]>; Jason Gunthorpe <[email protected]>;
>> [email protected]; [email protected];
>> [email protected]; Krishnakant Jaju <[email protected]>
>> Subject: Re: [PATCH v5 3/5] hw/arm/smmuv3-accel: Allocate vEVENTQ for
>> accelerated SMMUv3 devices
>>
> ...
>>> Usually error_append_hint() is used to append a user friendly msg that
>>> helps the user to fix the problem.
>>> In qapi/error.h there is an example that relates to "Receive and
>>> accumulate multiple errors (first one wins):" by using
>>> error_propagate()
>> I didn't look very closely but just run a grep for "append" :)
>>
>> Yea, I think error_propagate() should work better.
> I am not sure error_propagate makes things better though.
>
> If I am not wrong, this is how the change will look like,
>
> static MemTxResult smmu_writel(SMMUv3State *s, hwaddr offset,
> uint64_t data, MemTxAttrs attrs)
> {
> + Error *err = NULL;
> Error *local_err = NULL;
>
> switch (offset) {
> @@ -1614,9 +1616,15 @@ static MemTxResult smmu_writel(SMMUv3State *s, hwaddr
> offset,
> s->cr0ack = data & ~SMMU_CR0_RESERVED;
> /* in case the command queue has been enabled */
> smmuv3_cmdq_consume(s, &local_err);
> + if (local_err) {
> + error_propagate(&err, local_err);
> + local_err = NULL;
> + }
> /* Allocate vEVENTQ if EventQ is enabled and a vIOMMU is available */
> - if (local_err == NULL) {
> - smmuv3_accel_alloc_veventq(s, &local_err);
> + smmuv3_accel_alloc_veventq(s, &local_err);
> + if (local_err) {
> + error_propagate(&err, local_err);
> + local_err = NULL;
> }
> break;
> case A_CR1:
> @@ -1724,8 +1732,8 @@ static MemTxResult smmu_writel(SMMUv3State *s, hwaddr
> offset,
> break;
> }
>
> - if (local_err) {
> - error_report_err(local_err);
> + if (err) {
> + error_report_err(err);
> }
> return MEMTX_OK;
> }
>
> And error_propagate() only will keep the first error.
>
> Instead, if we do below:
>
> @@ -1614,10 +1615,12 @@ static MemTxResult smmu_writel(SMMUv3State *s, hwaddr
> offset,
> s->cr0ack = data & ~SMMU_CR0_RESERVED;
> /* in case the command queue has been enabled */
> smmuv3_cmdq_consume(s, &local_err);
> - /* Allocate vEVENTQ if EventQ is enabled and a vIOMMU is available */
> - if (local_err == NULL) {
> - smmuv3_accel_alloc_veventq(s, &local_err);
> + if (local_err) {
> + error_report_err(local_err);
> + local_err = NULL;
> }
> + /* Allocate vEVENTQ if EventQ is enabled and a vIOMMU is available */
> + smmuv3_accel_alloc_veventq(s, &local_err);
> break;
If you want to accumulate, why don't you use the example in qapi/error.h:
* Receive and accumulate multiple errors (first one wins):
* Error *err = NULL, *local_err = NULL;
* foo(arg, &err);
* bar(arg, &local_err);
* error_propagate(&err, local_err);
* if (err) {
* handle the error...
* }
*
Eric
>
> This will report errors from both paths.
>
> Please let me know if there is a better way.
>
> Thanks,
> Shameer
>
